Trimming mechanism for sewing-machines



(N0 Modl.) 2 SheetsSheet 1.

T. 0. ROBINSON.

TRIMMING MECHANISM FOR SEWING MACHINES.

No. 286,164. Patented Oct. 2, 1883.

\A/ITNEESEE- N PETERS FhulwLikhagnphar. Washing'bll. n. c.

(No Model.) 2 Sheets-8heet 2.

T. G. ROBINSON.

TRIMMING MECHANISM FOR SEWING MACHINES.

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UNITED STATES ATENT met,

THOMAS o. ROBINSON, Or BOSTON, ASSIGNOR TO HIMSELF, AND EBENEZER n.WELCH, or CAMBRIDGE, MASSACHUSETTS.

TRIMMI'NG MECHANISM FOR SEWING-MACHINES.

SPECIFICATION forming part of Letters Patent No. 286,164, dated October2, 1883.

1 Application filed May 5, 1888. No model.)

provide certain improvements on the inventions'shown in my applicationsfor Letters Patent of the United States filed, respectively,

November 23, 1882, Serial No. 77,490, and

March 15, 1883, Serial No. 88,309. In the first of, said applications Ihave shown two presser-feet arranged to bear on the work, one in advanceof the other, and an elongated feed-dog formed to co-operate withbothpresser-feet.' In the second application I have shown an improved devicefor regulating the pressure of a reciprocating trimming-knife operatedby the power of a sewing-machine against a blade supported by the bed ofthe machine.

My present improvements consist, first, in an improved throat-plateadapted for use with the elongated feed-dog accompanying the twopresser-feet; secondly, in certain improved de vices for operating thevertical bar carrying the reciprocating trimming-knife; thirdly, in theprovision of a tip of rawhide or other comparatively frictionlessmaterial on the device whereby pressure is exerted on the reciprocatingblade; fourthly, in the provision of means for giving a draw out to areciprocating trimming-blade, all of which I will now proceed todescribe and claim. I

In the accompanying drawings, forming a part of this specification,Figure 1 represents a side elevation of a sewing-machine provided withmy improvements. Fig. 1 represents a piece of cloth as folded by myimproved folding devices. Fig. 2 represents a side view of the upperportion of the needle-bar, showing a in section the means for connectingit with lating device.

the device whereby it is operated. Fig. 3 represents a sectional view ofthe pressure-regu- Fig. 4 represents a transverse section of the bed ofthe machine and a side elevation of the reciprocating knife, the pressofthe bed. Fig. 6 represents an enlarged top view of the throat-plate.section on line 00 00, Fig. 6.

The same letters of reference indicate the same parts in all thefigures.

In the drawings, A represents the arm of a sewing-machine, B theneedle-bar, and O the presser-bar, having the presser-foot 0 located inthe usual relation to the needle-bar B.

1 represents the feed-dog, which is elongated, as shown in my firstabove-named application.

T represents the reciprocating trimmingknife, secured to a knife-bar, V.Said bar is reciprocated vertically by a suitable connection with thesewing-machineviz., a positivelyoperating grooved cam, W on the shaftW', and a bell-crank lever, V pivoted at VV' to a bracket on the arm ofthe machine. The lever W is engaged at one end with the cam W by a pinpassing through a slot, VV in the arm of the machine, and is connectedat the other end by a spring-pin, W with the knife-bar V. Said pinpasses through a quill or tube, W, projecting from a block, W having aFig. 7 represents a socket through which the knife-bar passes, and

has a spring which forces the pin into areeess the other arm extendsover the bed of the machine, the bend of the plate being at the lefthand of the operator.

1' represents a folding-blade, which is pivoted at r to a bracket orplate, 1", secured to the bed of the machine and located slightly inadvance of the folder 0*, as shown in Fig. 5. The blade 1' is at such aheight above the bed of the machine that when the presser-foot O isdepressed to bear on the work, as shown in seams Fig. 1, the blade 1 isopposite the center of l the trimmer. Thereeip'rocating blade T is thespace between the arms of thefolder, the

folder and guide together constituting an overseaming attachment adaptedto fold the work not required.

in the manner shown in Fig. 1. Byreference to Fig.4: it will be seenthat the lower arm of the folder is over the forward end of theelongated feed-dog, and therefore acts to press the material down uponsaid dog, and is an auxiliary presser. The pivoted blade r can be turnedon its pivot out of the way when it is I do not claim the folder securedto the I presse'r-foot, nor the pivoted folding-blade, in

respondingly slotted, as shownin Figs. 6 and 7, so that the throat-plateis almost entirely cut away back of the needle-hole u, a narrow tonguebeing thus formed, which contains the needle-hole and is connected withthe throatplate only at one end. To support the other end of said tongueI provide a bridge, 1;, attached at w to the under side of thethroatplate and projecting under the end of said tongue, so .as to forma bearing therefor, as

. shown in Fig. 7. The upper side of thebridge o is recessed at o toafford room for the feeda dog.

. machine.

9 represents the downwardly-proj ecting arm attached rigidly to theheadA of the machine, and having in its lower end the screw h, as shownin my second above-named application for Letters Patent, the screw itbeing adapted to press the reciprocating blade T against theco-operating fixed blade, which may be one edge of a slot in thethroat-plate through which the blade T passes, or, as I prefer, aseparate blade, a, suitably affixed to the bed of the My presentimprovement in this pressure-regulating device consists in providing thescrew 71. with a core, h, of rawhide, and a screw -follower, h adaptedto press said core outwardly from the screw. (See Fig. 3.) The rawhidecore bears directly against the reciprocating blade T and constitutes acomparatively frictionless bearing, which does not requ1re lubricatingand does not cause so much wear as the metal end of the screw hheretofore employed.

m represents a blower-casing attached-to the under side of the bed ofthe machine, and provided with a rotary fan-blower of ordinaryconstruction. pulley, m, which is belted to a pulley, m, on the shaft Wof the machine. From the casing m extends a pipe, 1), to a point overthe throatplate in close. proximity to the trimmer T. A continuous blastof air is thus supplied, which blows away the shreds and cuttings formedby The arbor of said blower has a in the present instance pivoted to theknifebar at l, as shown in Fig. 4, so asto be capable of oscillating.The portion T of the blade, which projects through the slot in thethroatplate, has a pin, T, which enters a diagonalv slot, T, in an armor extension on the fixed blade a. It will be seen that when the ma-'chine is in operation the diagonal slot will give the knife a drawingmovement, when it is cutting, the knife being th'us caused to make adraw cut, which is particularly effective on silk goods. I prefer toprovide the pin" T with a friction-roller to diminish its friction onthe slot. I do not limit myself, however, to the diagonal slot as ameans of giving the knife a draw out. The same result may be produced bya link, 15, pivoted at t to the lower end of the knife T, and at t to afixed support, as shown in Fig. 4.".

I reserve for a future application all patentable matter shown but notclaimed herein.

I claim- 1. The combination, with the feed-dog widened back of theneedle,.the throat-platecut away or slotted to leave a tongue containingthe needle-hole u, said tonguebeing connected with the plate only at oneend, as shown, and the bridge 12, secured to the under side of thethroat-plate, so as to support the outer end of said tongue, andprovided with ,a recess, 0, adapted to receive the feed-dog, as setforth.

2. The combination of the knife-bar V, the needle-bar-operatin g shaftWV, having the positive cam NV, and the bell-crank lever W, pivoted to afixed support on the arm of the machine, and engaged at one end withsaid cam, and having a pivotal connection at its other end with theknife-bar, as set forth.

3. The combination, with the reciprocating blade T, of thepressure-adjusting device h, having the rawhide core h,'bearing directlyagainst said blade and in rubbing contact therewith, whereby frictionbetween ihe device h and blade T is reduced, as set forth.

4. The pressure-regulating screw h, having the rawhide core h andscrew-follower h", combined with the arm 9 and reciprocating blade T, asset forth. I

5. The combination of the knife-bar V, the reciprocating blade T,pivoted to the knifebar and provided with a pin, T in its lower portionand the fixed cutting-blade having a diagonally-slotted arm receivingsaid pin, as set forth.

In testimony whereof I have signed my name to this specification, in thepresence of two subscribing witnesses, this 24th day of April, 1883.

THOMAS C. ROB'INSQN.

